DMFC阳极催化剂的性能影响因素研究

Some factors affecting the performance of anodic catalysts for direct methanol fuel cell

为提高DMFC阳极催化剂的催化活性,采用化学还原法制备了Pt-Ru/C催化剂,考查了还原剂浓度、还原溶液pH值及还原温度对催化剂性能的影响;利用粉末微电极测试循环伏安曲线和稳态极化曲线,考核了上述催化剂在0.5 mol/L CH3OH和0.5 mol/L H2SO4混合溶液中,对甲醇阳极催化氧化活性的影响.XRD和TEM分析表明:还原溶液pH为8,80℃还原时,制备的催化剂性能好于其他工艺制备的催化剂;Pt-Ru合金催化剂颗粒在碳载体上分散均匀,粒径较小,平均为4 nm左右.还原剂浓度对催化剂性能有一定影响,还原剂浓度不宜过大.

This research aims to thus to lower the catalyst loading increase the utilization of platinum - ruthenium alloy （ Pt - Ru） catalysts and in anodes for methanol electrooxidation. The DMFC anodic catalysts, Pt - Ru/C, were prepared with different concentration of the reducing agent, pH values of the solution, and temperatures of reduction. Their performances were tested by cyclic vohammetry and potentiostatic polarization with a powder microelectrode from them in 0. 5 mol/L CH3OH and 0. 5 mol/L H2SO4 solution. The size, its distribution and crystallinity of the deposited catalysts were determined by means of high - resolution transmission electron microscopy and X - ray diffraction. The catalyst prepared with a solution of pH 8 at 80℃ showed the best catalytic performance for methanol electrooxidation. It had a more homogeneous distribution of Pt - Ru alloy in carbon. Its size is small, about 4nm. The catalyst performance was affected by the concentration of reducing agent which should be small.